gabi Senior Member Joined: 6 Nov 2006 Posts: 133 Location: Tel-Aviv, Israel Expertise: I like coffee
Espresso: PID Silvia Grinder: Mazzer Mini
Posted Mon Mar 19, 2007, 3:18pm Subject: Special report Gaggia vs. Silvia using Terroir light roast - A newbie perception
Bottom-line - We were able to easily pull great shots using unmodified (new) Rancilio Silvia + MM + Terroir 's "Daterra, North Italian Style Espresso" We were not that lucky with my Gaggia Classic (problems seems temp stability and high pressure), but nevertheless we manage to get nice shots with some temp surfing.
The Full Story: Everything started when I posted a request for help finding an easy to use blend for a newbie on Gaggia-Classic + Rocky in this forum Peter from Terroir Coffee reply to my post saying he would like to see how does his coffee works on the Gaggia
We met Sunday afternoon, Peter brought his Mazzer-Mini, his new Rancilio Silvia as a reference machine and tons of Terroir coffee Peter said that the optimal temp for us should be around 195F (give or take 2-3 degrees ) so we used his thermocouple fitted PF, purging water until we reached 195F and then took the shots --Note-- The Silvia PF didn't fit the Gaggia (which has a non-standard 58 PF), so we put it under the shower head without locking the PF in to measure water temp. This is not very scientific, but was as good as we could do.
We started with the "Daterra, North Italian", which we didn't manage to get right at first, I thought the coffee tasted like eating a brownies dough We then switched to the "La Providencia, Huehuetenango, Guatemala (Vienna roast)", still not getting it right
At that point we tried measuring temp again, and we found out that when purging water to get the temp down to 195, the temp continues to drop when pulling the shot resulting with an average temp of 185F. The reason might be that the Gaggia boiler is so small (100cc) so when fresh water replace the purged water the temp drops too fast We decided going for the reveres direction, we purged some water than waited for the boiler to start working and took measurements after the heating element was disengaged We found that when the boiler turned off, the water temp was 185F, but about 8 seconds later the water temp reached 195 and we were able to pull about 70cc before the temp dropped bellow 190F
So we started testing with this method, purge some water (1-2 oz.) wait for the boiler to get on, and about 8 seconds after it was turned off we pulled the shot. Peter was dosing 13g, the problem with the light roast is that you can easily fit 20+ grams of grinds into the stock 14 gr. Gaggia basket (the same probably apply to other standard baskets) so Peter brought with him a smaller double filter-basket. The smaller basket was about 57mm so my 58mm tamper was too big, and Peter's 55mm tamper was too small, so we never got what people will consider a perfect tamping Also while Peter was paying attention to distribution he didn't play with WDT or anything like this, simply leveling the grind (again nothing perfect)
With the new temp surfing method we had much better shots, most were smooth with very little bitterness or sourness A day before I grab fresh Terroir 's "Daterra, South Italian Style Espresso" in Simon's which I used on that same morning making some ok shots after dialing in my Rocky, dosing 16gr with no temp surfing We tried the South Italian using the new technique (13g + temp surfing) and got very nice shots, but I liked the Vienna roast of the Guatemala better.
We then went back again to the North Italian, using the same temp surfing technique. This time we didn't get the "brownies dough" effect, but the flavor felt flat compare to the Guatemala. We also had early blonding (5-10 seconds into the shot) which Peter thought might mean temp is too high We put the thermocouple again, and found that the temp went to over 200F Some more testing revealed that the Gaggia boiler got engaged with water temp of 195-198 bringing the water well over 200F ( we measured 212F few times) The new work around was to empty the boiler (100cc) and then repeat the old system (8 seconds after boiler turned off). This time we were able to get very nice shots from the North Italian which became my favorite
At that point Peter turned to his Silvia (which was new for him with plastic still covering the drip tray), the technique was very simple, with the light off (i.e. boiler is not working) Peter purged some water until he saw 193F, then he removed the thermocouple PF (which was locked inside the Silvia) and attached the PF with the basket inside We had to dial in the MM (Silvia needed coarser grind than the Gaggia) to the correct range (one or two tries which we didn't taste) The shot didn't have the amazing colors/texture you see in pictures, just ok flow. Peter stopped the shot after few seconds of blonding (he believes that some blonding actually improves the shot) Then we tasted the espresso which was easily the best I had in my life, very sweet and complex with chocolate and fruit flavor We repeated the shot, same grind, 13g dose, again draining some water until Fluke showed 193F locking in and pulling the shot to the same results We tried another one this time without the thermocouple, purge some water wait for the steam to stop (yes Silvia seems to overheat like the Gaggia) then lock in and pull the shot This time we were not as lucky, the shot was similar to those we did with the Gaggia, still nice and clean, but much less complex - some hard tone seem to cover all the subtle flavors we got before.
Before Peter left we tried under dosing the Gaggia to 12.5g which to me was the best I had from the Gaggia, but not close to the Silvia shots
This morning I ran two shots of "Daterra, North Italian" with my Gaggia/Rocky using 13g, WDT, some leveling (Peter left me the small basket and lots of coffee to abuse) tamp (the first shot with the Gaggia small plastic tamper, and the second shot with my RB 58 which none of them really fit) temp surf and pulled the shots Both were very nice - clean no bitterness and very little sourness, not the same league like the two great shot we got on Silvia, but still very nice
My conclusions: 1) Peter is a great guy !! 2) Temp surfing is necessary on both Gaggia/Silvia 3) Terroir is not hard to work with, the trick seems to be under dosing, and maybe waiting 3-5 seconds into blonding 4) Distribute and tamp seem to be less important (I saw channeling with the great shot from Silvia which didn't change the fact that taste was great) 5) Temp is important, but not as some people make it to be - even with the great shots we didn't use anything which could make us consistent on 1 degree, we probably fluctuated by few degrees. On the other hand working 10 degrees over or under is going to ruin your shot 6) Getting a stable temp on Gaggia is not easy - probably because it has such a tiny boiler. Silvia was able to stay closer to target with her 3.5 times bigger boiler 7) Something else on the Gaggia was blocking it from getting great shots, probably the pressure - we got about 30% more volume from the Gaggia than Silvia with the same grind/dose. Maybe the Gaggia is over extracting and so masking the subtle flavors --I need to play with under dosing, maybe 12g will do the trick-- 8) It seems very easy to get great shot from Silvia, if you know how to temp surf. I don't know how will Silvia behave if left on for long time maybe the temp profile will change like the Gaggia. I'm sure people here know the answer. 9) And yes, I really like the Daterra, North Italian
Few questions we will need to answer - 1) What was the pressure on the Silvia ? We didn't have pressure gauge, but Peter said he will check at work 2) What was the pressure on the Gaggia ? Harder to check as the Gaggia uses non-standard PF. 3) Are there better temp-surf technique for the Gaggia ? I posted a question in the machine forum which hopefully someone will be able to answer 4) My temp measurement on the Gaggia should be taken with a grain of salt (ok, lots of salt) since I was not able to get a fitting PF. I just measured the water going out the shower head. Hopefully I will be able to do something better soon. I can borrow a Fluke from work, I will try and understand how to get and connect Thermocouple to it and maybe will be able to get more accurate results
I will like to thank Peter for putting all this effort to help a newbie in his quest for a better coffee It was a great experience for me meeting someone who cares and knows so much about coffee and getting to see him at work Hopefully this post will help other people to get better coffee
poison Senior Member Joined: 11 Aug 2004 Posts: 1,080 Location: www.westcoastroasting.com Expertise: I live coffee
Espresso: Silvia? Nah, teh PuLs3R!!! Grinder: Maestro Plus, Super J deal Drip: Cone filter Roaster: RK drum
Posted Tue Mar 20, 2007, 12:15pm Subject: Re: Special report Gaggia
Peter IS an awesome dude, and not shy about helping others. Two thumbs up!
Nice report! One thing stands out: the inconsistancy of both machines, even under the oversight of a pro. You got one good shot from Silvia which you couldn't replicate. Those looking at buying a Silvia should take note.
Posted Tue Mar 20, 2007, 12:27pm Subject: Re: Special report Gaggia
poison Said:
Peter IS an awesome dude, and not shy about helping others. Two thumbs up!
Nice report! One thing stands out: the inconsistancy of both machines, even under the oversight of a pro. You got one good shot from Silvia which you couldn't replicate. Those looking at buying a Silvia should take note.
Like I said to Gabriel on another thread Nate, PID'ing a Silvia is the best way to fly! Unless you like the ritual of temp surfing for years.., I got tired of it. {:-/
SL28ave Senior Member Joined: 19 Mar 2004 Posts: 796 Location: Rockville, MD Expertise: I live coffee
Grinder: Baratza Virtuoso Drip: Technivorm
Posted Tue Mar 20, 2007, 2:32pm Subject: Re: Special report Gaggia vs. Silvia using Terroir light roast - A newbie percep
Thanks for the kind words, all.
An awesome report! Way to document! This is critical info. I agree with pretty much all of Gabriel's thoughts on the matter.
Nate, we pulled 3 shots from the Silvia, being 2 with a Scace and one without. Both shots with the Scace tasted perfect, IMO. Then on the spur of the moment I wanted to see if I could do it without the Scace, by purging water a few seconds after the boil, and that one shot came out good but not as good as with the Scace... So far with my Silvia at work I've tried about 6 shots, all with a Scace, and 5 of these blew me away... I'll learn how to temp-surf with the Silvia, and see what my good shot/bad shot ratio is... of course I'm open to having 3rd party assessments too.
Gabriel, the Silvia water pressure is a little over 10 bars. I'll try to set up a gauge for the Gaggia.
This is all very stimulating! I'll definitely have more info to give soon.
Nice report! One thing stands out: the inconsistancy of both machines, even under the oversight of a pro. You got one good shot from Silvia which you couldn't replicate. Those looking at buying a Silvia should take note.
Anyway, great report!
Actually we were able to get two consistent great shots from Silvia as soon as the grind was more or less correct using the thermocouple to check when we reach the correct temp The third one which went wrong (but was still nice) was done without any temperature control - simply purging water out until the steaming stopped It should be possible to do something better with temp surfing if you know the temp profile of the Silvia (the machine was new for Peter) So it is 2 out of 3 for Silvia and 0 out of 30 for Gaggia (when filtering out the shots which were not dialed correctly) I'm not seriously suggesting that 2 out 3 is statistically significant, it just shows that maybe it is a possibility
Now don't get me wrong, we were able to get nice shots most of the time on the Gaggia, just not a single great one I don't say that you can not get them, just that more research is needed (with the thermocouple attached to a Gaggia PF this time)
What surprised me most in this experience is how not-very-difficult (notice that I don't say easy) is to make nice shots with a modest setup (the $200 Gaggia Espresso is internally the same as the classic)
Since then I was able to repeat the nice Gaggia shots 4 out of 5 times, which three weeks ago I would have considered great accomplishment.
SL28ave Senior Member Joined: 19 Mar 2004 Posts: 796 Location: Rockville, MD Expertise: I live coffee
Grinder: Baratza Virtuoso Drip: Technivorm
Posted Tue Mar 20, 2007, 2:53pm Subject: Re: Special report Gaggia vs. Silvia using Terroir light roast - A newbie percep
And as a quick side-note:
When I say these Silvia shots taste perfect, I mean they taste better than shots I've had using similar beans on some La Marzocco, Synesso, Robur, Brewtus, LS Vivaldi setups etc etc.... I hope to find out why.
gabi Senior Member Joined: 6 Nov 2006 Posts: 133 Location: Tel-Aviv, Israel Expertise: I like coffee
Espresso: PID Silvia Grinder: Mazzer Mini
Posted Tue Mar 20, 2007, 3:21pm Subject: Re: Special report Gaggia
CraigA Said:
Like I said to Gabriel on another thread Nate, PID'ing a Silvia is the best way to fly! Unless you like the ritual of temp surfing for years.., I got tired of it. {:-/
I'm considering that option already. The funny thing is that being a straight espresso guy I was seriously considering a PID Alexia + M4 as my first setup. Then I got cold feet, worrying that I won't be able to make anything drinkable without milk to hide the mistakes (and Alexia was suppose to have this low cycle between milk/coffee) so I decided to start easy with the Gaggia/Rocky setup and upgrade later if I ever develop enough skills
I'm now considering upgrading my machine - I think any PID would be nice, but since I bought my setup from WLL I will need to upgrade to something they carry and maybe add the PID later. The two options seems to be the new Silvia with changeable OPV (I still suspect the pressure on my Gaggia is set too high) or the Pulsar which can change the brew pressure and suppose to be easier to temp surf than Silvia (so maybe a PID won't be needed)
It's reading at least one bar higher than 3 Marzoccos I checked today, all with a stagnant environment. The Marzoccos' internal gauges were reading ~8.9 bar while shots were being pulled. Weird!
I'll do whatever it takes to get an accurate and precise readout. Help?! It would be fairly accurate to take stagnant pressure readings from machine to machine, right?
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